Engines operating with variable fuels, such as flex-fuel engines, may have more than one fuel system, and thus more than one fuel tank. For example, engines may be configured with a dual fuel system including two fuel tanks for two varieties of fuels, such as gasoline and an ethanol fuel. Such systems, however, require a vehicle operator to keep track of each fuel's usage, fuel levels in each tank, and to fill each tank accordingly.
Accordingly, various approaches have been developed for assisting vehicle operators in refueling fuel tanks of vehicles with multiple fuel systems. One example approach is illustrated by Cheiky in US 2009/0255508. Therein, a smart fueling system computes various fueling options for the vehicle operator at a filling station. Specifically, the smart fueling system may communicate with the fueling pump and determine a refueling mixture based on the fuel options available at the pump, the level of fuel in each vehicle fuel tank, and the vehicle's operating conditions.
However, the inventors herein have recognized potential issues with such an approach. As one example, the refueling options may be biased towards the fueling options available at the fueling station. As another example, the refueling options presented may not take into account the different rates of fuel usage based on each fuel's properties. For example, a driver who prefers fuel economy may be provided with a higher amount of ethanol fuel and a lower amount of gasoline fuel due to the presence of more ethanol fueling options at the fueling station. Consequently, due to ethanol fuel's lower heating value, engine fuel economy may be degraded. In another example, a driver who prefers high engine performance may be provided with a lower amount of ethanol fuel and a higher amount of gasoline fuel due to the presence of fewer ethanol refueling options at the fueling station. Consequently, due to a reduction in the availability of ethanol fuel, the driver may have reduced access to the charge cooling effects of ethanol, and thus engine performance may be degraded.
As another example, the refueling options presented may not take into account environmental conditions, or account for different fuel usage rates of different fuels under different environmental conditions. These may include environmental conditions prevalent along the vehicle's travel route when refueling is requested, as well as predicted environmental conditions related to a future trip plan (such as a destination and travel route planned immediately following the refueling). The environmental conditions may include, for example, humidity, temperature, altitude, weather predictions (such as, rain or snow predictions), etc. Similarly, the refueling may be based on an average vehicle drive history, which may be substantially different from the vehicle's trip plan following refueling. Thus, a refueling profile based on the drive history may not be optimal for the drive plan following refueling. For example, the drive history may be based on driving at areas with a higher humidity and/or a lower altitude. Under such conditions, an ethanol fuel may be used at a lower rate. Following refueling, the vehicle may be driven in an area with a lower humidity and/or at a higher altitude, where a higher rate of ethanol fuel usage may be anticipated. Thus, a refueling profile based on the average drive history and average environmental conditions may lead to a faster depletion of the ethanol fuel following refueling. As such, this may lead to degraded engine performance after refueling. Furthermore, the fuel tank may need to be refilled earlier than anticipated.
Thus, in one example, some of the above issues may be addressed by a method of selectively fueling a vehicle including a first fuel tank with a first fuel and a second fuel tank with a second, different, fuel. In one embodiment, the method may comprise, displaying a fueling profile to a vehicle operator, the fueling profile based on predicted future environmental conditions of a vehicle trip plan.
In one example, a vehicle may include a dual fuel system with a first fuel tank storing a first fuel and a second fuel tank holding a second, different, fuel. A refueling indication may be automatically provided when a fuel level in one or both fuel tanks falls below respective threshold levels. Alternatively, a vehicle operator may communicate a refueling request to the engine controller through a user interface, such as an interactive display device, on the vehicle dashboard. In response to the refueling request, the engine controller may display one or more fueling profiles to the vehicle operator (for example, on the display device), based at least on engine operating conditions and environmental conditions. Specifically, the controller may anticipate a fuel usage rate for the different fuels in the multiple fuel system based on the environmental conditions and properties of the fuel. In one example, the first fuel tank may store a first fuel with a lower effective octane, such as gasoline, while the second fuel tank may store a second fuel with a higher effective octane, such as ethanol. Herein, the displayed fueling profiles may anticipate the likelihood of engine knock based on the vehicle's travel plan and the environmental conditions at the destination and along the planned route. Further, the displayed fueling profiles may take into account the charge cooling properties and knock mitigating effects of ethanol fuels, and anticipate fuel usage rates for the ethanol fuel and the gasoline fuel accordingly. In another example, the displayed fueling profile may take into account an anticipated amount of boost usage based on the vehicle's travel plan and predicted future environmental conditions, and adjust a fuel usage rate for the ethanol fuel and the gasoline fuel based on the effect of ethanol fuel on boost performance. The fueling options displayed may be further based on operator indicated preferences and constraints (such as monetary constraints for the cheapest fueling option, or time constraints for the closest fueling option), engine operating conditions, vehicle loads (e.g., trailer towing loads or other loads), driver performance history (e.g. fuel economy-driven or performance-driven), driver aggressiveness, terrain (e.g., hill, gradients, road grade, etc.), etc.
In one example, the displayed fueling profiles may include details such as fuel type, a fuel ratio between the fuels to be received (such as, a ratio between fuel volumes added in each tank), fuel octane content of the received fuels, etc. Each fueling profile may further include details of one or more fueling stations (where fuel according to the fuel type, fuel ratio etc. of the corresponding fueling profile can be received), as well as directions to direct the vehicle to the fueling station. An operator may select a fueling station from the displayed fueling stations based on the selected fueling profile. Thus, a fueling station may be chosen such that it is capable of providing fuel according to the selected fuel profile, thereby enabling the vehicle operator to take advantage of each fuel's attributes while also providing the requested engine performance. Further, if the selected fueling station is capable of smart refueling, the fueling profile may be communicated to the fueling station (for example, through wireless communication), and information regarding a fuel type of a received fuel may be received from the fueling station and displayed to the operator during the refueling operation.
In this way, a fueling system may facilitate refueling operations by reducing the amount of operator effort required. By displaying fueling profiles that take into account vehicle operating conditions, vehicle performance history, vehicle travel plans, and environmental conditions, vehicle refueling operations may be simplified for a vehicle operator, and may be performed with minimal operator input, without affecting vehicle performance.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.